1. Field of The Invention
This invention relates to processes and compositions for the topical application of .beta.-adrenergic receptor agonists to effect retraction of the hair in a hair-bearing skin area. More particularly, it relates to processes for the treatment of hair-bearing skin areas in humans for the purpose of retracting the hair in the area thereby to make the area appear and feel smooth.
2. Description of The Related Art
The processes of this invention have a wide variety of applications, for example, in conjunction with depilatory waxes, chemical depilatories, bleach creams and the like. They have particular application in conjunction with shaving processes and compositions. To simplify the description of the invention, emphasis will be placed on its application to such shaving processes and compositions as exemplary of the broader concept of the invention.
The compositions used in the processes of this invention can be applied to any of a variety of hair-bearing skin areas. When used in conjunction with the shaving processes and compositions, for example, the compositions used in the invention may be applied to the legs, axillary vaults, facial skin, etc. of the subject. When used in conjunction with bleach creams, the compositions may also be applied to hair-bearing areas of the head and extremities thereby making the bleaching process appear more effective.
One of the criteria of a "good" shave is that, after the shave, the area should appear and feel smooth. This can be achieved by a so-called close shave in which the razor, be it manual or machine, cuts the hair as close as possible to the skin. To that end, it has been proposed to apply a piloerection agent to the area to be shaved prior to the actual shaving process. The erection of the hair facilitates the achievement of a close shave.
Sympathomimetic agents causing piloerection are disclosed in copending and commonly assigned application, Ser. No. 33987, filed Apr. 2, 1987U.S. Pat. No. 4,853,216, which describes and claims the use of compositions containing .alpha.-adrenergic receptor agonists to elicit a pilomotor response of hair erection.
Another method for achieving a smooth appearance and feel is to cause the hair to retract, i.e., recede into the skin, after the shaving process is complete. It has now been discovered that topical application of .beta.-adrenergic receptor agonists to the hair-bearing area will surprisingly elicit a pilomotor response which will cause the hair to retract.
As is known in the pharmacology art, adrenergic receptors are two general types. There are .alpha.-adrenergic receptors and .beta.-adrenergic receptors. For example, norepinephrine is a classic .alpha.-adrenergic receptor stimulator while isoproterenol is a classic .beta.-adrenergic receptor stimulator. Such compounds are also known as agonists. Compounds having the opposite effect are known as antagonists. The compounds utilized in this invention are .beta.-adrenergic receptor agonists.
It is surprising to find that .beta.-adrenergic receptor agonists will effect a pilomotor response of relaxation of the arrectores pilorum muscles causing the hair in the hair-bearing area to retract. As is evident from the above identified copending application, it was the original understanding of the inventors thereof that all sympathomimetic agents including .alpha.- and .beta.-receptor agonists caused pilomotor erection of the hair -------- not retraction. So far as is known, there have been no previous teachings or suggestions of the use of .beta.-adrenergic receptor agonists to effect pilomotor retraction of hair. U.S. Pat. No. 4,038,417 describes the topical application of such compounds for the treatment of psoriasis.